Faster flight refresh interval

500ms for the VAB is pretty good, but its really clunky looking in
flight and in flight we have lighterweight updates.

Signed-off-by: Lamont Granquist <lamont@scriptkiddie.org>

MechJeb2/MechJebLib/Utils/BackgroundJob.cs

@@ -1,10 +1,9 @@
+#nullable enable
 
 using System;
 using System.Threading;
 using System.Threading.Tasks;
 
-#nullable enable
-
 namespace MechJebLib.Utils
 {
     // TODO:

MechJeb2/MechJebModuleStageStats.cs

@@ -3,7 +3,6 @@
 using JetBrains.Annotations;
 using MechJebLib.Simulations;
 using Unity.Profiling;
-using Debug = UnityEngine.Debug;
 
 namespace MuMech
 {
@@ -176,7 +175,9 @@ private void TryStartSimulation()
                 if (Vessel is null) return;
             }
 
-            if (_stopwatch.IsRunning && _stopwatch.ElapsedMilliseconds < 500)
+            double refreshInterval = HighLogic.LoadedSceneIsEditor ? 500 : 100;
+
+            if (_stopwatch.IsRunning && _stopwatch.ElapsedMilliseconds < refreshInterval)
                 return;
 
             _stopwatch.Restart();